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Engel & Cunningham’s Trichrome for Muscle Fibres, Types I & II

Engel & Cunningham's Trichrome

for Muscle Fibres, Types I & II



  • Harris alum hematoxylin
  • Solution A
    Chromotrope 2R0.6g
    Fast green FCF0.3g
    Phosphotungstic acid0.6g
    Acetic acid, glacial1mL
    Distilled water99mL

    Adjust to pH 3.4 with 1N NaOH.

  • Solution B
    Acetic acid, glacial0.2mL
    Distilled water100mL

Tissue Sample

Unfixed frozen sections of liquid nitrogen quenched muscle. Sections should be 5-10µ in thickness. The fibres should be in cross section, as close to a right angle to their length as possible.


  1. Cut cryostat sections and dry at room temperature.
  2. Stain nuclei with Harris’ hematoxylin for 5 minutes.
  3. Rinse well with distilled water.
  4. Place into solution A for 10 minute.
  5. Rinse with solution B for a few seconds to differentiate.
  6. Dehydrate with ethanol.
  7. Clear with xylene and mount with a resinous medium.

Expected Results

  • Nuclei  –  blue
  • Type I fibres  –  green with a red cast
  • Type II fibres  –  green


  • Both fibre types are green overall, but type I fibres contain more red staining granular material and have a red cast.
  • This is a modification of Gomori’s trichrome.

Safety Note

Prior to handling any chemical, consult the Safety Data Sheet (SDS) for proper handling and safety precautions.


  1. Culling C.F.A., (1974)
    Handbook of histopathological and histochemical techniques, Ed. 3
    Butterworth, London, UK.
    Engel & Cunningham, (1963)
    Rapid examination of muscle tissue.
    An improved trichrome method for fresh frozen biopsy specimens.
    Neurology, vol.13, pp.921